Typical liquid crystal display cells include TN-LCD (twisted nematic liquid crystal display devices) which are utilized in the fields of clocks, watches, electronic calculators, pocket computers, word processors and personal computers. The information density on one display has been increased with an increase in information to be processed by OA apparatuses in recent years. Conventional TN-LCD can no longer meet the requirements of high multiplex drive systems, particularly word processors and personal computers with respect to the quality level of visual field angle and contrast.
Under such circumstances, STN (super twisted nematic) -LCD have been developed by Sheffer et al (SID '85 Digest, p. 120 (1985)) and Kinukawa et al. (SID '86 Digest, p. 122 (1986)) and are becoming wide spread for use in the display of high information processing in word processors and personal computers.
In a STN-LCD, the control of the angle formed by an aligning surface and a liquid crystal molecule, that is, a pertilt angle, is an important factor which has a significant effect on yields, etc. in the preparation of liquid crystal display cells.
Known orientation treatments include a method wherein the pretilt angle is controlled to a high pretilt angle of about 20.degree. by oblique evaporation of SiOx. In practical application, there is known a method wherein the pretilt angle is controlled to about 5.degree., for example, by rubbing an organic film such as Sunever 150 (a product of Nissan Chemical Industries, Ltd.). Further, various aligning layers have been developed and are used to control the pretilt angle to 5.degree. to 10.degree. by rubbing method. It is known that the formation of a stripe domain becomes more difficult with an increase in pretilt angles, and yields in the preparation of liquid crystal cells are increased. However, there is much difficulty in preparing constantly stable aligning layers at a pretilt angle of 5.degree. to 10.degree. by rubbing method under the existing circumstances.